11 ideas
| 9616 | A set is a collection into a whole of distinct objects of our intuition or thought [Cantor] |
| Full Idea: A set is any collection into a whole M of definite, distinct objects m ... of our intuition or thought. | |
| From: George Cantor (The Theory of Transfinite Numbers [1897], p.85), quoted by James Robert Brown - Philosophy of Mathematics Ch.2 | |
| A reaction: This is the original conception of a set, which hit trouble with Russell's Paradox. Cantor's original definition immediately invites thoughts about the status of vague objects. |
| 15896 | Cantor needed Power Set for the reals, but then couldn't count the new collections [Cantor, by Lavine] |
| Full Idea: Cantor grafted the Power Set axiom onto his theory when he needed it to incorporate the real numbers, ...but his theory was supposed to be theory of collections that can be counted, but he didn't know how to count the new collections. | |
| From: report of George Cantor (The Theory of Transfinite Numbers [1897]) by Shaughan Lavine - Understanding the Infinite I | |
| A reaction: I take this to refer to the countability of the sets, rather than the members of the sets. Lavine notes that counting was Cantor's key principle, but he now had to abandon it. Zermelo came to the rescue. |
| 17644 | Metaphysical realism is committed to there being one ultimate true theory [Putnam] |
| Full Idea: What makes the metaphysical realist a 'metaphysical' realist is his belief that there is somewhere 'one true theory' (two theories which are true and complete descriptions of the world would be mere notational variants of each other). | |
| From: Hilary Putnam (Why there isn't a ready-made world [1981], 'Causation') | |
| A reaction: This is wrong!!!!! Commitment to one reality doesn't imply that only one comprehensive theory is possible. Theory-making (at least in any human language, or in mathematics) is an inherently limited activity. |
| 17648 | It is an illusion to think there could be one good scientific theory of reality [Putnam] |
| Full Idea: The idea of a coherent theory of the noumena; consistent, systematic, and arrived at by 'the scientific method' seems to me to be chimerical. | |
| From: Hilary Putnam (Why there isn't a ready-made world [1981], 'Failure') | |
| A reaction: I sort of agree with this, but it definitely doesn't make me an anti-realist. |
| 17643 | Shape is essential relative to 'statue', but not essential relative to 'clay' [Putnam] |
| Full Idea: Relative to the description 'that statue', a certain shape is an essential property of the object; relative to the description 'that piece of clay', the shape not an essential property (but being clay is). | |
| From: Hilary Putnam (Why there isn't a ready-made world [1981], 'Intro') | |
| A reaction: Relative to the description 'that loathsome object', is the statue essentially loathsome? Asserting the essence of an object is a response to the object, not a response to a description of it. This is not the solution to the statue problem. |
| 19553 | Commitment to 'I have a hand' only makes sense in a context where it has been doubted [Hawthorne] |
| Full Idea: If I utter 'I know I have a hand' then I can only be reckoned a cooperative conversant by my interlocutors on the assumption that there was a real question as to whether I have a hand. | |
| From: John Hawthorne (The Case for Closure [2005], 2) | |
| A reaction: This seems to point to the contextualist approach to global scepticism, which concerns whether we are setting the bar high or low for 'knowledge'. |
| 17642 | The old view that sense data are independent of mind is quite dotty [Putnam] |
| Full Idea: Moore and Russell held the strange view that 'sensibilia' (sense data) are mind-independent entities: a view so dotty, on the face of it, that few analytic philosophers like to be reminded that this is how analytic philosophy started. | |
| From: Hilary Putnam (Why there isn't a ready-made world [1981], 'Intro') | |
| A reaction: I suspect the view was influenced by the anti-psychologism of Frege, and his idea that all the other concepts are mind-independent, living by their own rules in a 'third realm'. Personally I think analytic philosophy needs more psychology, not less. |
| 19551 | How can we know the heavyweight implications of normal knowledge? Must we distort 'knowledge'? [Hawthorne] |
| Full Idea: Those who deny skepticism but accept closure will have to explain how we know the various 'heavyweight' skeptical hypotheses to be false. Do we then twist the concept of knowledge to fit the twin desiderata of closue and anti-skepticism? | |
| From: John Hawthorne (The Case for Closure [2005], Intro) | |
| A reaction: [He is giving Dretske's view; Dretske says we do twist knowledge] Thus if I remember yesterday, that has the heavyweight implication that the past is real. Hawthorne nicely summarises why closure produces a philosophical problem. |
| 19552 | We wouldn't know the logical implications of our knowledge if small risks added up to big risks [Hawthorne] |
| Full Idea: Maybe one cannot know the logical consequences of the proposition that one knows, on account of the fact that small risks add up to big risks. | |
| From: John Hawthorne (The Case for Closure [2005], 1) | |
| A reaction: The idea of closure is that the new knowledge has the certainty of logic, and each step is accepted. An array of receding propositions can lose reliability, but that shouldn't apply to logic implications. Assuming monotonic logic, of course. |
| 19554 | Denying closure is denying we know P when we know P and Q, which is absurd in simple cases [Hawthorne] |
| Full Idea: How could we know that P and Q but not be in a position to know that P (as deniers of closure must say)? If my glass is full of wine, we know 'g is full of wine, and not full of non-wine'. How can we deny that we know it is not full of non-wine? | |
| From: John Hawthorne (The Case for Closure [2005], 2) | |
| A reaction: Hawthorne merely raises this doubt. Dretske is concerned with heavyweight implications, but how do you accept lightweight implications like this one, and then suddenly reject them when they become too heavy? [see p.49] |
| 17645 | An alien might think oxygen was the main cause of a forest fire [Putnam] |
| Full Idea: Imagine a Venusian lands on Earth and observes a forest fire, and says 'I know what caused that - the atmosphere is saturated with oxygen!'. Thus one man's 'background condition' can easily be another man's 'cause'. | |
| From: Hilary Putnam (Why there isn't a ready-made world [1981], 'Causation') | |
| A reaction: You can't sweep 'the' cause of a fire away so easily. There is always oxygen on Earth, but only occasional forest fires. The oxygen doesn't 'trigger' the fire (i.e. it isn't the proximate cause). |